Telephone system.



PATENTED JULY 17, 1906.-

G. V. BEAVER. TELEPHONE SYSTEM. APPLIOA'I'ION FILED JULY 5. 1902.

UNITED STATES PATENT OFFICE.

CHARLES VERNON BEAVER, OF ANITA, IOWA.

TELEPHONE SYSTEM.

Specification of Letters Patent.

.Eatented July 17, 1906.

Application filed July 5, 1902- .Serial No. 114.518-

To aZZ whom, it may concern:

Be it known that I, CHARLES VERNON BEA- VER, a citizen of the United States, residing at Anita,-in the county of Cass and State of Iowa, have invented a new and useful improvement in telephone systems whereby the main-line wire or wires of a telephoneline may be kept free from all instruments except at the time they are in actual use, of which the following is aspecification.

My invention relates to systems of electrical communication by induction, and especially to telephone systems,.and has for its principal object to provide a multiparty telephone-line comprising a main line and an auxiliary line, the latter paralleling the main line and in inductive relation thereto, having the instruments of the various subscribers normally disconnected from the respective lines except when said instruments are in immediate use, so that however large the number of instruments employed in connection With the system may be the line-wires are free of all instruments other than those momentarily employed in sending and receiving the call or the message.

The invention is illustrated in the accompanying drawings, in which Figure 1 illustrates the particular arrangement of my improved system as applied to a grounded return-circuit. Fig. 2 illustrates a modification in which the signaling and transmitting apparatus are adapted to be connected with the main line, which is a grounded return-circuit, and the signal-receiving instrument and the telephone-receiver are located in a secondary loop-circuit having a branch in inductive relation to the main circuit. Fig. 3 shows the signaling and transmitting instruments adapted to be connected in series with the main line, while the telephone-receiver and signal-receiving instrument are located in the secondary circuit, which is a grounded loop. Fig. 4 shows a modification in which the main and auxiliary line-wires are formed as complete metallic circuits and the several instruments are adapted to be connected in arallel with the respective lines. Fig. 5 is a rther modification showing complete metallic-circuit main and auxiliary lines with means for independently connecting the transmitting andslgnaling apparatus in series with the main line, while the telephone-receiver and signal-receiving instrument are adapted to be similarly connected in the secondary circuit.

In the particular embodiment of my invention illustrated in Fig. 1, a indicates a main line employing a ground return, and 1) indicates a second or auxiliary line which is arranged in inductive relation to the main line a. The two lines are preferably held in close parallel proximity by suitable insulating spacing-pieces applied at proper intervals to bind the wires together. It will be evident that a series of electrical impulses propagated in the main line a will roduce similar electrical effects in the line so that electrical signaling or telephonic currents transmitted by the line a will be reproduced inductively in the line b. As it is one of the primary objects of my invention to keep the main line a, free of all heavy resistances or inductances, such as will be produced by the ordinary telephone instruments, I propose to arrange the signaling apparatus and the telephonic transmitter in such relation to the main line that said instruments are only connected to said line while the instrument in question is being used. To this end at each subscribers station the main line a, is connected by a branch m, provided with a ground-wire. interposed in said branch m are two switches g and 25, adapted to connect a magneto G or equivalent signaling apparatus or a telephone-transmitter T to the line a through said branch m. In order to accomplish these objects, the generator G and the transmitter T are each located in normally open circuits terminating in contacts 6 e and i 1, respectively, so that when switch 9 is moved inwardly the generator G is connected between the main line a and the ground through said switch, and correspondingly when the switch If is pushed in transmitter T is connected between the main line and the ground. Each of said switches is preferably provided with a spring for returning it to its normal position, (illustrated in Fig. 1,) in which the generator and transmitter are disconnected from the line. The telephone-receiver and the signal-receiving apparatus are connected to the auxiliary line b by means of-connector n, which is grounded at z, and the instruments are so arranged that when the receiver R is upon the telephone-hook the circuit will be closed through the call-bell or equivalent signaling instrument S, and correspondingly when the receiver is removed from the hook the circuit through the signaling instrument is broken and a circuit through the said receiver R is main line a and operating the several signalreceiving mechanisms at the other sub.

scribers stations over a circuit substantially as follows: generator Gr, wire (1, switch-contact e, switch-bar f to wire m, thence to circuit-wire a, thence by way of grounded wire y, switch-bar j, contact 6, wire d back to the generator. The impulses in the main circuit a induce corresponding impulses in auxiliary-circuit wire 6, which pass to ground through the several subscribers bells or signal-receiving instruments S by way of circuits similar to the following: wire n, to the receiver-hook, switch-point signal S to ground, thence back to circuit-wire b. After sending this call the operator releases switch g, which is immediately withdrawn by its spring to break the generatoncircuit, and thereafter removes his receiver R from its hook, thereby establishing a circuit from circuit-wire b to the telephone-receiver to ground, as will be readily understood by those familiar with telephone practice. In order to communicate with the called subscriber, the calling subscriber presses the handle of switch 25 inward against the spring, thereby connecting his transmitter T with the main-line circuit as follows: lead-wire m,

switch-bar 3', contact i, wire it, transmitter T, wire it, contact t, switch-bar to ground y. The electrical impulses set up in the transmitter travel along the main circuit wire a, according to the circuit just traced, and induce similar impulses in the secondary wire I), which pass through the receiver-circuit n g 7c z of the called subscriber. It is understood, of course, that during conversation the parties conversing keep their receivers off their respective hooks. The party talking operates his switch 25 to close the transmittercircuit, but the listening party, however, may release the corresponding switch, permitting his transmitter-circuit to be opened and only closing the latter when he desires to communicate. By this modeof operation it is to be seen that the main wire a is free from all instruments except the generator G at the time of signaling or the transmitter T while the .party is speaking. Hence the propagation of the electrical impulses along the main circuit is unimpeded.

In the form of the invention shown in Fig.

2 the arrangement of the apparatus is sub stantially the same as that above described, the only material difference being that the auxiliary circuit b is constructed as a local circuit or loop at each subscribers station, having one of its branches arranged parallel to the main-line wire ct for a considerable distance, so that this parallel branch occupies an inductive relation with the main-line wire, and both the signaling impulses and the voicecurrentimpulses transmitted over said linewire a are reproduced inductivelyin the auxiliary wire I) and are accordingly transmitted through the local circuit to the signal-receiving device or the telephone-receiver, as the case may be.

In Fig. 3 the main line, which is normally free from all instruments whatsoever, is connected as a continuous series circuit through the lower connected contacts of the switches g and t at each station, and the transmitter and signaling-generator at any station are adapted to be connected in series in the mainline circuit a by means of switches t and g, respectively, which for this purpose are moved inwardly to break the direct connection of line a through said switches and to connect the generator G and the transmitter T, respectively, in series with said line a. For example, when the switch 9 is operated by the calling party the main-line circuit is broken at one set of the switch-points and the generator G is instantly cut in to bridge the break by way of the opposite switchpoints. As soon as the switch 9 is released it immediately breaks the generator-circuit and reestablishes the main-line circuit as before. A corresponding operation of the switch t breaks the main-line circuit at the lower switch-points and establishes the transmitter in the main-line circuit through the upper switch-points, which operation is reversed as soon as the switch is released.

The modification shown in Fig. 4 differs from that illustrated in Fig. 1 only in that the main and auxiliary lines are formed as complete metallic circuits (1 a and b I), respectively, and the various instruments are adapted to be bridged across the respective linesthat is to say, generator G and transmitter T are adapted to be connected in parallel between wires a and a by operating switches g and t, respectively, in substantially the same manner as described in connection with Fig. 1.

In the modified form of my invention; as illustrated in Fig. 5 complete metallic circuits are employed in the main and auxiliary lines; but in this case the various instruments are adapted to be connected in series in the respective linesthat is, by operating switch g. The main-line circuit is broken at the lower switch-points, and the generator G is immediately connected in series with the line a, and correspondingly when theswitch 13o t is operated the transmitter T is established in the line a substantially in the same manner described in connection with the apparatus illustrated in Fig' 3. It will of course be understood that the several signal-receiving devices S are in series in the auxiliary-line wires b b and that the telephone-receivers are cut into circuit when they are removed from their hooks.

So far as I am aware, it is broadly new to establish electric interconnection between a number of stations by providing a direct main line extending from one station to the others throughout the series and serving as a transmitting-conductor of and from the several stations, said main line being normally free from all instruments at all of the stations throughout the series, and therefore free from the ohmic and inductive resistance of said instruments and from all possible cross-fiow therethrough, and the several receiving devices at the various stations being located in auxiliary circuits in inductive relation to the main line. So far as I am aware, this is broadly new regardless of the particular type of transmitting or receiving apparatus employed in the system, for which reason I desire that my claims shall have a correspondingly broad interpretation.

Having thus described my invention, what I claim is 1. In a system of electrical communication between a number of stations, the combination of a direct main line extending from one station to another throughout the series and normally free from all instruments, and, therefore, free from the ohmic and inductive resistance of said instruments and from all possible electrical cross-flow therethrough, sending devices at the several stations adapted to be brought into operative connection with said main line, and receiving devices at the several stations located in auxiliary circuits in inductive relation to the main line.

2. In a system of electrical communication between a number of stations, the combinati on of a direct main line extending from one station to another throughout the series and normally free from all instruments, and, therefore, free from the ohmic and inductive resistance of said instruments and from all possible electrical cross-flow therethrough, signal-sending devices at the several stations adapted to be brought into operative connection with said main line, and signal-receiving devices at the several stations located in auxiliary circuits in inductive relation to the main line and switches for connecting and disconnecting the said sending and receiving devices to and from their respective lines.

3. In a system of electrical communication between a number of stations, the combina tion of a direct main line extending from one station to another throughout the series and normally free from all instruments, and, therefore, free from the ohmic and inductive resistance of said instruments and from all possible electrical cross-flow therethrough, telephone-transmitters and signal-sending devices at the several stations adapted to be brought into operative connection with said main line, and telephone-receivers and signalreceiving devices at the several stations located in auxiliary circuits in inductive relation to the main line, and switches for connecting and disconnecting the said sending and receiving devices to and from their respective lines.

CHARLES VERNON BEAVER.

Witnesses:

H. C. FAULKNER, O. M. MYERs 

